Abstract: Air is compressed in a compressor, purified in a purification unit, cooled by passage through a main heat exchanger and separated in a double rectification column comprising a higher pressure rectification column and a lower pressure rectification column. A stream of argon-enriched oxygen vapour is withdrawn from the lower pressure rectification column through an outlet and an argon product is separated from it in an argon rectification column provided with an argon condenser. Argon is condensed in the condenser by indirect heat exchange with a second stream of air at a pressure between the operating pressures of the columns. The second air stream is partially condensed and passed into a phase separator. A stream of liquid phase is withdrawn from the phase separator, is passed through a throttling valve and the condenser, in sequence. Further cooling for the condenser is thus provided.

Abstract: A cryogenic rectification system employing a double column and two auxiliary reboilers associated with one or two auxiliary columns wherein both lower purity oxygen and higher purity oxygen is produced.

Abstract: Air is compressed in compressors, cooled in a main heat exchanger, and separated into oxygen and nitrogen products in a double rectification column comprising a higher pressure rectification column and a lower pressure rectification column. A liquid oxygen product is withdrawn from the lower pressure column via a conduit. A liquid nitrogen product is also formed. An argon-enriched oxygen vapour stream is withdrawn from the lower pressure column through an outlet and has argon separated from it in an argon column. In order to help meet the requirements of the higher pressure column for reflux, a nitrogen vapour stream is withdrawn from the top of the lower pressure column, is warmed by passage through the heat exchanger, is recompressed in a compressor, and is liquefied by passage back through the heat exchanger from its warm end to its cold end and passage through a valve. A high liquid make and a high argon recovery can both be achieved.

Abstract: In a process for the production of gaseous oxygen under pressure at a variable flow rate, of the type in which air is distilled in an air distillation installation comprising a distillation apparatus (7) and a heat exchange line (6) to cool the air by heat exchange with the products from the distillation apparatus; liquid oxygen is withdrawn from this apparatus, brought to a vaporization pressure, vaporized and reheated under this pressure in the heat exchange line, this vaporization and this reheating being accompanied by a liquefaction of air in the air liquefaction passages (21; 21,21A) of the heat exchange line.

Abstract: Process and installation for the production of gaseous oxygen and/or gaseous nitrogen under pressure, of the type in which the air is distilled in a double distillation column (10) comprising a low pressure column (12) operating under a low pressure, and a medium pressure column (11) operating under a medium pressure. All the air to be distilled is compressed (in 1,4) to at least one high pressure of air substantially greater than the medium pressure, and the compressed air is cooled to an intermediate temperature. A portion of it is expanded in a turbine (5) to the medium pressure, before introducing it into the medium pressure column (11). The non-work-expanded air is liquified, then introduced after expansion (in 19, 20), into the double column; and at least one liquid product withdrawn from the double column is brought to the production pressure, and this liquid product is vaporized by heat exchange with the air.

Abstract: In this process for the distillation of air, of the type with a liquid oxygen pump (14) and with the vaporization of liquid oxygen under pressure, there are used, in addition to a principal compressor (1), at least three further compressors (9 to 11 ), of which two (9, 10) are mounted in series and supply the heat exchange line with air at a high pressure of the vaporization of oxygen. Air is withdrawn between these two further compressors, expanded to the medium pressure and introduced at the base of the medium pressure column (5), and at least one (11) of the three further compressors consumes the mechanical energy developed by the turbine (12).

Abstract: An air separation method and apparatus in which a stream of air is compressed in a compressor and purified in a unit. One stream of the resulting air is cooled in a heat exchanger and is separated in an arrangement of rectification columns comprising a higher pressure rectification column, a lower pressure rectification column, and a further rectification column for separating argon from an argon-enriched oxygen stream withdrawn from the lower pressure rectification column and the stream of resulting air is introduced into the higher pressure rectification column through an inlet. A second cooled, compressed, purified air stream is expanded in an expansion turbine and is introduced into the lower pressure rectification column. A third cooled, compressed, purified air stream is expanded in a second expansion turbine and is introduced into the higher pressure rectification column.